.png) Epsilon Indi Ab imaged by JWST MIRI. The star motif marks the position of its host star; whose light is blocked by a coronagraph. | |
| Discovery[1] | |
|---|---|
| Discovered by | Fabo Feng, et al. |
| Discovery date | 21 March 2018 (suspected since 2002) |
| Radial velocity | |
| Orbital characteristics[2][a] | |
| 28.4+10 −7.2 AU | |
| Eccentricity | 0.40+0.15 −0.18 |
| ~173.6 years[b] | |
| Inclination | 103.7°±2.3° |
| Star | Epsilon Indi A |
| Physical characteristics[2] | |
| 1.08 RJup[c] | |
| Mass | 6.31+0.60 −0.56 MJ |
| Temperature | 275 K (2 °C; 35 °F) |
Epsilon Indi Ab is a gas giant exoplanet orbiting the star Epsilon Indi A, about 11.9 light-years away in the constellation of Indus. The planet was confirmed to exist in 2018.[1] It orbits at around 28 AU (almost as far as Neptune from the Sun) with a period of around 174 years and a relatively high eccentricity of 0.4, and has a mass around 6 times that of Jupiter.[2] It was directly imaged using the James Webb Space Telescope in 2023[3] and the image was released in 2024.[4]
As of 2024[update], Epsilon Indi Ab is the nearest exoplanet to be directly imaged, and with a temperature of about 275 K (2 °C; 35 °F), is also the coolest exoplanet to be directly imaged, and cooler than all but one imaged brown dwarf (the exception being the planetary-mass WISE 0855−0714).[4] It is predicted, based on evolutionary models, to have a luminosity around to 6.31×10−8 L☉.[2]
The Epsilon Indi system also contains a pair of brown dwarfs, Epsilon Indi Ba and Bb, at a wide separation from the primary star. As such, this system provides a benchmark case for the study of the formation of gas giants and brown dwarfs.[1]
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